When the buggers first encountered humans in outer space, they killed many of them. The humans interpreted this as attempted genocide and defended themselves. But in fact the buggers assumed humans operated as a hive mind as they did, and that killing a single human would have no effect on the "organism" as a whole. This fundamental misunderstanding led to two major bugger-human wars, and finally to a concentrated assault on the bugger homeworld to wipe out their species once and for all before humanity was wiped out first.

They almost succeeded; one immature and cocooned bugger queen was preserved on a distant colony world of the buggers, and was eventually discovered by Ender Wiggin. He carried this queen until he arrived on Lusitania, three thousand years later, and allowed the queen to emerge and repopulate her species without human interference.

Slang in at least some parts of the USNavy for shooting a torpedo at another boat/sub from behind it and hitting its back end. The submariner who told me this wondered why I found it so funny, as he didn't know the sodomy definition (as seen in Webster 1913's entry) until I explained.

Bug"ger (?), n. [F. bougre, fr. LL. Bulgarus, a Bulgarian, and also a heretic; because the inhabitants of Bulgaria were infected with heresy. Those guilty of the crime of buggery were called heretics, because in the eyes of their adversaries there was nothing more heinous than heresy, and it was therefore thought that the origin of such a vice could only be owing to heretics.]